Control means for correlating supply of aspirating to aspirated fluids



A. DOBLE l VAmi! 27,1948.

CONTROL MEANS FOR CORREIJATINGl SUPPLY 0F ASPIRATING T0 ASPIRATED FLUIDS Filed ct. 21, 1944 Patentedl Apr. 27, 1948 CONTR()L MEANS FOR CORRELATING SUP- ILY OF ASPIRATING T FLUIDS ASPIRATED Abner Doble, Chicago, Ill., assignor to Stanley Steam Motors Corporation, Chicago, Ill., a corporation of Delaware Application October 2l, 1944, Serial No. 559,749 7 claims. (ol. 15s-42.1)

This invention relates to control means for burners, more particularly to means for controlling vthe supply of fuel and air to the burner of an elastic fluid or steam generating boiler, and the invention has for an object the provision of improved burner control means of this character.

combustion system for supplying heat to the boiler. In one well-known type of vehicle power plant, air is supplied by means of a fan or blower to suitable carburetion means which may comprise a venturi in which a fuel nozzle is arranged, the fuel being supplied to the nozzle from a suitable reservoir.

Fuel is aspirated from the nozzle by the air, and the resulting combustible mixture is ignited by a suitable igniter such as a spark plug, the burning gases passing' into the fire box of the boiler where heat from the gases'is transferred to the water in the boiler to generate steam, after which the gases are exhausted to the atmosphere. The blower for supplying combustion air may be driven by an electric motor and an auxiliary turbine, in the manner described in applicant's copending application Serial No. 536,658, filed May 22, 1944, Patent No. 2,379,887, issued July 10, 1945, and entitled Steam power plants.

Damper means are ordinarily provided in the air supply duct for controlling the supply of combustion air, and it has heretofore been proposed to employ suitably controlled electromagnets for operating the damper. Such electromagnets, however, impose heavy loads on the electrical system of the bus or similar vehicle and under certain conditions may lfail to effect proper operation of the damper, which is subject to sticking and is at times diflicult to operate. Dimculties are encountered, such as improper combustion and excessive smoking, if the supply of combustion air is not properly correlated with the fuel supply, and, accordingly, it is a further object of this invention to provide improved means for operating the damper to insure that combustion air will be supplied to the burner only when an adequate supply of fuel is available for proper combustion.

In carrying out the invention in one form, a burner is provided having a supply duct for combustion air and damper means in the duct'for controlling the supply of air. Fluid pressureresponsive means are provided for opening and closing the damper means and a pump for producing a flow of fluid is connected to the pressureresponsive means so that the flow of fluid exerts pressure on the pressure-responsive means to operate the damper means to one position. Valve means responsive to an operating condition of the burner are provided for altering the fluid flow produced by the pump so as to change the pressure on the pressure-responsive means and effect operation of the damper means to another position.

More particularly, a steam boiler is provided having a burner or combustion system including carburetion means arranged in the air duct, so that fuel will be aspirated by the air passing through the d-uct into the fire box of the boiler. A fuel pump is provided with an outlet conduit connected to the fluid pressure operating means for the damper and toa fuel reservoir forming part of the carburetion means. Valve means responsive to the quantity of fuel in the reservoir kcontrols the flow of fuel to the reservoir and functions to close or partially close the connection :from the pump to the reservoir when an adequate supply of fuel is available in the reservoir, thus increasing the pressure exerted by the fuel from the pump on the fluid pressure operating means so as to open the damper. When the supply of -fuel in the reservoir falls below a predetermined minimum, the valve means opens further to increase the fuel flow into the reservoir and hence relieves the pressure of the fuel on the pressure operating means and permits closure of the damper.

For a more complete understanding of the invention, reference should now be had to the drawings in which:

Fig. 1 is a diagrammatic representation, partially in section, of a steam generator and a combustion control system embodying the present invention; s

Fig. 2 is a sectional elevational view of the damper and its operatingfmechanism shown schematically in Fig. 1.

. Referring now to the drawings, the invention is shown as embodying a 'steam boiler l0 which is preferably of the series tube type having a fire box to which a combustible mixture of fuel and air is supplied, the mixture being ignited by a spark plug I2. n Air is supplied by a blower or fan I3, drivenv by asuitable motor Il and an auxiliary turbine (n'ot shown), as is described in the applicants above-'referred-to cop'ending andere y application. In the air supply conduit I5 there is arranged a damper I8 and a fuel nozzle I1 having its discharge opening arranged in the throat 'of a venturi I8, the nozzle I1 then being supplied with fuel through conduit II. The air in passing through the venturi I8 aspirates fuel from the fuel nozzle I1.

The fuel nozzle I1 forms part of a carburetion system including a fuel reservoir I9 to which lfuel is supplied by an electrically driven pump 2|, which may be of the Well-known diaphragm type, or may be a motor driven rotary or reciprocating pump of suitable construction. The fuel pump 2| delivers fuel to the reservoir I9 through a conduit 20, and valve means comprising a valve seat 23 and a needle or stem 24 operated by a float 25 through ,a lever 26 pivoted at 21 are provided for controlling the supply of fuel to the reservoir. The float 25 is adjusted to close the needle valve when the fuel in the reservoir approaches the level represented by the broken line 28. A fuel conduit II, the lower end 29 of which extends below the liquid level 28, serves to supply fuel to the nozzle I1 under the aspirating action of the air.

The damper I6 and its pressure-operating mechanism 30, as shown in detail in Fig. 2, are supported in the air supply conduit I5, the damper I6 being pivoted at 3| to a supporting housing 32 and being operated by means of a crank arm 33 connected by a pin 34 to an operating stem 35, which is in turn connected to a disc 31 supported on a flexible Idiaphragm 35. A spring 38 arranged around the operating stem 35 biases the diaphragm to a downward position, and it will be observed that in this position of the diaphragm the damper is in the full line or closed position. When the diaphragm moves upwardly, the damper moves to the dotted or open position, the damper being operated through the medium of fluid pressure exerted on the diaphragm by fuel entering the chamber 39 through conduit 40 and conduit 20 from the fuel pump 2I. `A vent 4'I is provided in the damper housing to connect the upper `side of the diaphragm to atmosphere.

The pump 2I`thus serves the dual purpose of supplying fuel to the reservoir I9 and supplying fluid pressure to operate the damper I6 toits open position when an adequate supply of fuel is present in the reservoir, the spring 38 acting to close the damper when insuicient fluid pressure is available. The fluid pressure damper operating means 30 and the fuel reservoir I9 are effectively arranged in parallel relation with each other so that the fluid pressure built up in the damper operating means by the fuel supplied thereto is dependent upon the amount of fuel being supplied to the reservoir I9.

The boiler I is provided with the usual temperature responsive and pressure responsive means for controlling the supply of electric energy to the fuel pump 2l, the blower motor I4 and the ignition system for the spark plug I2. As shown, energy is supplied from a suitable source represented by the battery 50 through a manually operable switch I and a conductor 52 to a pressure-responsive contact 53 adapted to engage a bus bar 54. Also engaging the bus bar 54 is a temperature-responsive contact 55 to which the various electrical devices are connected through a conductor 56. Thecircuit for the electric fuel pump 2I extends through the conductors 56 and 56', and the circuit for the blower motor I4 extends through the conductors 56, 51 and 68 to one side of the blower motor, the other side of which is connected by avconductor I9 to a suitable ground connection.

The ignition system for the spark plug I2 comprises the usual spark coil L82 having a primarywinding 83 and a secondary winding I4 which is connected to the spark plug by aconductor 6l. The energizing circuit for the primary winding 83 extends through the conductors 5I, 91 and 58, a pair of breaker contacts 59 and, and by way of a conductorv 8i to the primary winding 6I. The breaker contacts 59 and 69 are of the type well known in the art adaptedvto be operated to make and break the electrical circuit periodically, and for purposes of illustration the operating mechanism for the contacts is shown as comprising a co-operating cam and arm 56 and 61, the cam being connected to the shaft of the blower motor I4.

Although any suitable temperature-responsive and pressure-responsive means may be employed, the temperature-responsive means for operating the contact 551s shown as comprising an expansible tube 19 positioned within the boiler III and connected by a suitable operating rod 89 to the pivoted arm on which the contact 551s mounted. The pressure-responsive means for operating the contact 53 is shown somewhat diagrammatically as comprising a pressure-responsive device 11 connected through suitable linkage to the contact 53 and adapted to be operated by steam pressure supplied thereto from the boiler outlet conduit 15, through which steam is supplied from the boiler to the throttle of the steam engine.

When the temperature and pressure conditions within the boiler I0 are such that the contacts 53 and 55 both engage the bus bar 54, the electric fuel pump 2I will be energized to supply fuel through the conduit 20. If it is assumed that the amount of fuel in the reservoir I9 is insufllcient for proper combustion, the float 25 will occupy a lposition such that the needle valve 24 will be open and consequently fuel is supplied to the reservoir I9 through the needle valves. Under these conditions pressure will not be built up inthe chamber 39 and the spring 38 maintains the damper I6 in the closed position shown in Fig. 1. As soon as the level of the fuel within the reservoir I9 rises sufciently to. close or at least partially close the needlevalve, part of the fuel-supplied by the pump 2l will be diverted through ther conduit 40 to the chamber 39, and pressure will be built'4 up against the underside of the diaphragm 36. As soon as this pressure attains-a sufficient value, the diaphragm will be moved so as to operate the damper I8 to the open position shown in broken lines in Fig. 2 against the force of the spring 38.

The consequent ow of combustion air through the conduit I5 and past the fuel nozzle I1 will cause fuel to be drawn from the reservoir I9, and since the ignition system for the spark plug I2 is energized, ire willbe supplied to the boiler I9. The fuel level within the Areservoir I9 will drop as fuel is withdrawn through the nozzle I1 and the needle valve 24 will open slightly to pe'rmit fuel to ow into the reservoir from the pump 2|. This opening of the needle valve results in a decrease in the pressure existing in the chamber 39, but under normal conditions this decrease in pressure will not be suillcient to effect movement of the damper to its closed position.

will continue to flow through the conduit Il, however, since blower I l is also driven from the aux-v iliary turbine, and fuel will be drawn from the reservoir I9. As soon as the noat 25- causes a further opening of the needle valve 24 the pressure within the chamber 39 will immediately be relieved, since the spring 3B and the diaphragm 36 now operate as a plunger to force fuel out of the chamber 39 through the conduit 40 and into the reservoir I9 through the needle valve. Consequently, the damper is virtually immediately operated to its closed position to cut of! the flow of air.

Failure or inadequacy of the supply of fuel provided by the fuel pump 21 due toany cause, such. as failure of the pump itself, breakage of the fuel-conduit, or lack of fuel in tank 22, like-- wise results in closure of the damper I8 to shut down the burner, the operation being the same as described above in connection with a stoppage of the fuel pump caused by opening of the temperatureor pressure-responsive contacts.

Thusit will be seen that the Vpressure operati ing means 30 not only effects positive operation of the damper between its open and closed position without imposing any additional load on the electrical system of the unit, but in addition insures that the damper will be closed if an inadequate supply of fuel is available at the fuel nozzle i1. Thus positive control of the burner is obtained and improper combustion is avoided.

While I have shown particular embodiments of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modiflcations may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

Having thus described my invention, what I claim and desire to obtain by Letters Patent is:

l. In a burner for a steam boiler, a 4duct for supplying combustion air to said burner, damper means in said duct having open and closed positions for controlling the flow of said combustion air therethrough, iluid-pressure-responsive means for operating said damper means between said positions, aspirating means associated with said duct for supplying fuel thereto including a fuel reservoir, pump means for producing a ilow of fuel to said" reservoir, said aspirating means being constructed to supply fuel when the fuel level in said reservoir has a normal value greater than that at which aspiration'fails, means connecting said pump means to said fluid-pressureresponsive means whereby said fuel exerts pressure on said pressure-responsive means to operate said damper means to said open position, said fluid pressure means being effective to operate said damper means to said closed position upon a predetermined decreasev in the pressure exerted by said fuel, valve means responsive to a predetermined decrease in the fuel level in said. reservoir from said normal value for decreasing the resistance to flow of said fuel from said pump to said reservoir thereby to effect said predetermined decrease in the pressure on said pressure-responsive means, and means responsive to boiler heat conditions for stopping and starting the flow of fuel from said pump.

2. In a burner, a duct for supplying combustion air to said burner, damper means in said duct having open and closed positions for controlling the flow of said combustion air therethrough, fluid-pressure-responsive means for 0perating said damper means between said posi- 6 tions, aspiratlnz means associated with for supplying fuel thereto including a fuel reservoir, pump means forV producing a now of fuel to said reservoir, said aspirating means being constructed to supply fuel when the fuel level in said reservoirl has a normal value greater than that at which aspiration fails, means connecting said pump means to said iluid-pressure-responsive means whereby said fuel exerts pressure on said pressure-responsive means to operate said damper means to an open position when said fluid pressure is above a predetermined mimmum, said fluid pressure means being effective to operate said damper means to a closed position upon a decrease of said uid pressure below said predetermined minimum, and valve means responsive to a predetermined decrease in the fuel level in said fuel reservoir from said normal value decreasing the resistance to flow of said fuel from said pump to said reservoir thereby to decrease the pressure on said pressure-responsive means below said predetermined minimum.

3. In a burner, 'a duct for supplying combustion air to said burner, damper means in said duct` having open and closed positions for controlling the flow of said combustion air therethrough, iluid-pressure-responsive means for operating said damper means, a fuel reservoir, pump meansfor producing a flow of fuel to said reservoir, aspirating means-associated with said air supply duct for supplying fuel to said air supply duct when air is flowing therein, a conduit projecting into said reservoir connecting with said aspirating means, the extent of the projection into said reservoir determining the amount of fuel available for aspiration, means connecting said pump means to said fiuid-pressure-responsive means whereby said fuel exerts pressure on said pressure-responsive means to operate said for aspiration for altering said flow of said fuel from said pump to change the pressure on said pressure-responsive means.

4. In a burner for a steam boiler, a duct for supplying combustion air to said burner, damper means in said duct for controlling the flow of combustion air therethrough, fluid-pressure-responsive means for operating said damper means", a fuel reservoir, pump means for producing a flow of fuel to said reservoir, aspirating means associated with said air supply duct including a conduit for aspirating the fuel from said reservoir to said air supply duct when air is flowing therein, said conduit and reservoir being constructed to supply fuel to said burner only when the amount of fuel in said reservoir is greater than a certain value, means connecting said pump means to said fiuid-pressure-responsive means whereby said fuel exerts pressure on said pressure-responsive means to operate said damper means to said open position, said fluid-pressure-responsive means being effective to operatel said damper means to said closed position upon a predetermined decrease in the pressure exerted means responsive to boiler heat conditions for ma ductv 2,44o,sao

starting and stopping the flow of fuel from said pump.

5. In a burner, a duct for supplying combustion air, a damper in said duct having` open and closed positions for controlling the flow of` air therethrough, fluid-pressure-responsive means for operating said damper between said positions, a fuel reservoir, means for supplying fuel to said reservoir, conduit means connecting said fuel reservoir and said burner for supplying fuel from said reservoir to said burner, said conduit means being constructed. to supply fuel from said reslevel in said reservoir from said normal value ervoir only when the fuel level in said reservoir is greater than a certain value, means connecting said fuel supply means to said fluid-pressure-responsive means for operating said damper to said open position while said fuel level is above a pre-` determined minimum, and means responsive to a predetermined decrease of said fuel level from said minimum value cooperating with said fuel supply means for operating said damper to said closed position.

6. In combination, a supply duct for a first fluid, means in said duct for controlling the y,flow of said first uid therethrough, fluid pressure responsive means for operating said flow-controlling means between open and closed positions, means for producing a flow of said second fluid, a reservoir for receiving at least a portion of said second fluid, aspirating means associated with said first fluid supply duct for aspirating said second fluid from said reservoir when said first fluid is flowing in said supply duct, said aspirating means being constructed to supply fluid when theiluid level in said reservoir has a normal value greater ,than that at which aspiration fails, means connecting said flow-producing means to said fluid pressure responsive means whereby said second fluid exerts pressure on said pressure responsive means to operate said flow controlling means to one position, said fluid pressure responsive means being effective to operate said flow controlling means to a second position upon a predetermined change in vthe pressure exerted by said second fluid, and` valve means responsive to a predetermined change in the fluid for altering the flow of said second fluid to change the pressure on said pressure responsive means.

7. In combination, a supply duct for a first fluid, damper means in said duct having open and closed positionsfor controlling the flow of said first fluid therethrough, fluid pressure responsive means for operating said damper means between said positions, pump means for producing the flow of a second fluid, a -reservoir for receiving at least a portion of said second fluid, aspirating means associated with said first uid supply duct for aspirating said second fluid from said reservoir when said first fluid is flowing in said supply duct, said aspirating means being constructed to supply fluid when the uid level in said reservoir has a normal value greater than that at which aspiration fails, means connecting said pump means to said fluid pressure responsive means whereby said second fluid exerts pressure on said pressure responsive means to operate said damper means to an open position, said fluid pressure responsive means being effective to operate said damper means to a closed position upon a predetermined decrease in the pressure exerted by said second fluid, and valve means responsive to a predetermined decrease in the fluid level in said reservoir from said normal value for altering said flow of said' second fluid to decrease the pressure on said pressure responsive means for causing operation of said damper means to its closed position.

ABNER DOBLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,385,845 Scott July 26, 1921 1,493,919 Cunningham May 13, 1924 1,651,060 Janette Nov. 29, 1927 1,684,079 White Sept. 11, 1928 2,100,678- Schwander Nov. 30, 193'7 

